Nobody's Hero
by Little Cinch
Summary: SPOILERS through episode 10 x 18 (Book of the Damned), AU after that. As the Mark of Cain slowly destroys Dean Winchester, Castiel discovers it's killing him, too. Destiel angst. Rating for language and dark themes.
1. Chapter 1

**SPOILERS through episode 10 x 18 (Book of the Damned) and obviously AU after that. This takes place the same day as the end of the episode. This came at me like a giant tidal wave, and hopefully I can finish it before the next episode airs and spoils all my thoughts.**

**This is currently intended NOT to have a happy ending. At all. So be warned.**

**Please let me know if you see any mistakes, either in editing or in canon. Thanks!**

**Disclaimer: I don't own Supernatural. I just like it lots and want to play with the characters for a while.**

* * *

Castiel hesitated in the doorway of Charlie's room. Officially, it was a spare bedroom, but Charlie had already made it her own in a way the angel had never quite managed. The easy way she seemed to belong wherever she happened to be made him a tiny bit envious, deep down. Though he had his Grace fully restored, it seemed his time as a human had left an emotional mark on him.

He cleared his throat softly and asked, "May I come in?"

Charlie looked up from where she was sorting clothes into the dresser. Apparently she and Dean had stopped for more than food and beer while they were out. She gave him a bright grin. "Hey! Of course. What's the word, Tyrael?"

"But...I am not- Tyrael is-" He broke off in confusion.

Laughing, she waved him in. "Sorry! It's a gaming thing! I didn't mean-" She froze and her eyes popped wide in shock. "Oh my God! Is there a real Tyrael?"

"Well, yes. Though we were never what humans would call 'close', he was a gifted warrior, and I was honored to fight by his side many times. I'm sorry to say he was killed some few centuries ago."

Charlie's mouth hung open long enough that Castiel wondered if he'd somehow said something wrong. Finally, she simply exclaimed, "Holy shit!"

The angel frowned, uncertain what to make of her response. He edged back toward the door to escape before he made things worse.

She shook her head as though to clear her thoughts and beckoned to him again with a wave of her hand. "No, no – never mind, sorry! Come in! Did you need something?"

He took one hesitant step into the room. "Something you said earlier. Despite my time spent among humans and _as_ one, I still have difficulty interpreting some human mannerisms."

Dropping to sit on the bed with a bounce, Charlie leaned back against the headboard. "Okaaay?"

"I don't always recognize when I'm being teased."

She tipped her head, waiting curiously for him to finish.

"Was your offer of friendship genuine?"

Charlie's face softened and she patted the mattress in front of her. "Oh, Cas, honey, of course! Can I call you Cas? I know we just met, but with all the crap we've been through with those Winchester boys, I think that kind of automatically makes us BFFs!" And at Castiel's uncertain look, she clarified gently, "Friends. I want us to be friends."

The angel relaxed a little and sat on the edge of the bed where she'd indicated. "Then...may I confide in you?"

"Ooh! Are we dishing already? Awwwwesome!" she sang out. Then she sobered and asked, "Seriously, though, I love that you're here, but why me and not Dean or Sam?"

"I feel an outside perspective would be helpful." It was the truth, if not all of it.

She nodded, accepting the explanation. "All right, hit me! Er, tell me, I mean," she quickly corrected herself.

"We've been searching for a cure for the Mark of Cain for some time now and are no closer to an answer than we ever were. Though he masks it well, Dean's condition worsens by the day. However, what I find even more worrisome is his deterioration of spirit."

Charlie pursed her lips. "He's definitely not as feisty as usual. How bad is it, do you think?"

"It's bad." Castiel scowled at the carpet. "I am afraid. If he won't fight the influence of the Mark with his usual degree of obstinance, it will destroy him. Soon."

"We're doing everything we can, Cas. He's still resisting, and we're still looking for an answer."

The angel took a deep breath before continuing. "I know that. I do. But with my Grace restored, I can see the Mark's darkness eroding his soul, consuming it. He won't be able to hold it off, and-" He broke off, clenching his jaw shut.

"And what?" prompted Charlie.

Castiel ducked his head, his residual human feelings causing heat to flood his face. "I can't watch it happen. If Dean Winchester has to die, he should be throwing punches and flinging insults. Not like this. He's already given up, and it's...it's more difficult to accept than I would have thought," he finished quickly.

"You think he wants to die?"

"No. But I believe he won't fight death when it comes for him."

Charlie leaned forward to brush his forearm with her fingertips. "How do you feel about that?"

His body didn't need oxygen anymore, but Castiel found himself breathing hard as he considered it. "I don't know. There's too much, and all of it hurts. I'm afraid. I'm helpless to fix him, and I can't bear seeing him so hopeless. When I think that he might let himself die, I feel a terrible, aching hole inside me. I want to tear things apart, smite things. I want to...to _shake_ him until I can make him see what he's doing to himself. What he's doing to me."

He looked down, surprised to see Charlie had slipped her hand into his while he was talking and was holding it tightly. She scooted around to sit beside him and leaned her head against his shoulder, all the while rubbing her thumb soothingly over his.

"Does he know you love him?"

Castiel blinked. "What?"

"Have you told him you love him?" she repeated.

"Well... No?"

Her thumb continued its hypnotic path. "You can still help him. We're all looking for a cure, but that's not all he needs. Until we find a way to free him of that thing, he needs a reason to hang on. Something to fight for."

He found himself at a loss for words.

She hopped up and pulled Castiel to his feet before dragging him toward the door. Grinning, she gave his hand a squeeze. "Good talk, bestie!" she chirped. Then her bright smile melted into something more genuine. "Just think about it, okay?"

And with a gentle push, she ushered him out into the hallway and closed the door.


	2. Chapter 2

**SPOILERS through 10 x 18 (Book of the Damned). This chapter is written with the assumption that Sam is keeping the fact that he didn't burn the Book of the Damned a secret from everyone, not just Dean.**

**The title of this fic is from a song of the same name by The Strange Familiar. It's my mental theme song for writing this.**

**Disclaimer: I still don't own Supernatural.**

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Castiel was too restless to sleep – not that he really had to anymore, but he was in the habit. Plus his body – his vessel – was still adjusting to his restored Grace, and sleep would help him recover more quickly. But his conversation with Charlie left him with too much to think about. He wandered out to pace the library for a while before finally sitting on one of the couches there and frowning at the wall.

He looked up at the soft sound of footsteps.

"Cas, hey." Sam greeted the angel quietly as he appeared from the hallway leading to the living quarters.

"Sam. Are you also unable to sleep?"

Dragging his fingers through his hair, Sam sighed gustily. "Oh, you know. Brain won't shut up. How about you? Do you even need to sleep anymore?"

Castiel shrugged – a very human habit he'd picked up along the way in addition to sleeping. "Not really, but I have come to enjoy it for the most part. Tonight, however, sleep eludes me."

"I hear that," Sam agreed as he sat at the table covered in ancient texts, manuscripts, and files from the Men of Letters' archives. He paused and studied the angel for a moment. "So how are you doing? What's on your mind that you can't sleep?"

"Dean."

Laughing with no trace of mirth, Sam said, "So what else is new?"

"When I saw him last, he wasn't so passive about his situation as he seems to be now. His resignation toward what he considers the inevitable outcome of bearing the Mark of Cain makes me...uneasy," Castiel answered him literally.

"Yeah," Sam agreed. "I know. He's scaring the crap out of me, too."

They fell quiet, each to his own thoughts. The only sounds in the bunker were the hum of the ventilation system and the rustle of turning pages.

"You said Dean made you burn the Book," Castiel spoke up at last.

"Uh, yeah. That's right. He said it was calling to him, that anything we might get from it wouldn't be worth the evil that came with it." Sam shifted in his chair and scratched behind his ear.

Castiel tucked his hands into the pockets of his overcoat and hunched down into the couch cushions. "That book was our best chance to find a cure. Do you believe the risk outweighed the chance to save Dean? Or is he just unwilling to save himself?"

The hunter's brow knitted. "I don't know, Cas. I wish I did." He looked up, and the angel could see how badly Sam wanted to be reassured that everything would be all right again. "The Mark's already killing him, isn't it? Killing who he is?"

Pain flashed through Castiel, leaving a deep ache in both his body and his Grace. He desperately wished he could give Sam the reassurance he needed. "Perhaps."

He stood, abruptly ending the distressing conversation. "I'm going to bed. Goodnight, Sam."

Sam pinned him with eyes full of sorrow. "Night, Cas."

Castiel made his way back through the halls, but paused outside the door of the room he was using. Dean's room was directly across the hall from Cas's, and he eyed the door in the dim light. Dean had made it clear he didn't like being watched while he slept, but the angel slipped into his room anyway, cloaking himself from view just in case. What Dean didn't know wouldn't hurt him. Besides, he was only doing it to observe and evaluate the hunter's condition.

With his 'mojo' back, Castiel had no trouble seeing Dean in the darkness, his body tense and twisted into his bedding. At dinner that night, he'd actually laughed with the others and appeared to have a good time. For a fleeting moment, seeing that had made Castiel happier than he'd felt in a long time. But the taut lines of Dean's jaw and forehead were obvious signs of the stress the hunter was under. He suffered, even in sleep.

The ache inside the angel flared again sharply. Dean grew worse every day, and Castiel could do nothing to stop it. He would give anything to be able to take the Mark from him. He already felt Dean's pain acutely – he just wished he could take it for him completely. It was already tearing him apart.

Castiel moved closer to the figure tangled up on the bed. Feather-light, he touched two fingers to Dean's forehead and reached out with his Grace to ease the man's restlessness, and hopefully let him sleep more peacefully. When he took his hand away, he could feel the dark pull of the Mark clinging to his Grace – black, heavy, and evil. It made him feel sick.

As he watched, the deep lines on Dean's face eased just a little. He didn't relax completely, but Castiel would take anything he could get. He knew it would only be worse again tomorrow.

The angel considered what Charlie had said to him. He'd never told Dean that he loved him. Of course he loved him. And he was fairly certain the hunter knew it, at least on some level. Sometimes he even thought Dean might love him, too, but neither of them had ever expressed it in words.

He frowned down at the man before him. Charlie was wrong. Telling Dean something like that when he was already so fragile could only be a mistake. Even if Dean handled the revelation well, all it would give him is another reason to feel guilty. The hunter already felt responsible for far more than he should. If Dean knew how Castiel felt, it wouldn't give him some miraculous reason to keep fighting for his life. Instead, he'd double down on his facade of normalcy just to keep from worrying the angel.

Cas didn't want to see Dean suffer. Eventually, the Mark would succeed in pulling Dean into violent madness, and when it did, Castiel was certain that watching it happen would kill him, too.

Here in the bunker, the only thing Castiel could focus on was Dean and his flagging will to live. If he wanted to help Dean, he needed to leave. Out there, he'd be able to search for a cure without distraction. With his restored Grace, he would have access to more resources than before. Clearly, the best way to help Dean was to cure him, and he could only do that by leaving.

Resolute in his decision, Castiel reached down to the hunter's forehead again. Through the soft touch of his Grace, he said his goodbyes and tried to tell Dean how much he loved him. It would only be a subconscious impression left behind when the man awakened, but he told himself it was the best he could do. It wasn't a selfish choice – none of it was. It was all for Dean. He had to do it to save Dean.

As he left the room, he paused in the doorway for one last look at his hunter before returning to his own room to pack a bag.


	3. Chapter 3

**Quick reminder that if you require your angst to be tempered with a happy ending, this is NOT the story for you! Run away! No happiness to be found here.**

**Disclaimer: Supernatural does not belong to me. **

* * *

Castiel paused at the bottom of the steps leading out of the bunker and hitched his duffel higher onto his shoulder. Before he'd become human, he'd had no need for baggage. Before, he traveled unburdened by _things_. But now, despite being an angel again, his time as a human had left him...sentimental.

He looked up the staircase in front of him. Once he climbed it and passed through those doors, he wouldn't be back until he found a cure. He needed to do this, but found he couldn't make his feet move. Not yet. Leaving was the last thing he wanted, but he couldn't stay and watch Dean be slowly consumed by the Mark. Out there, beyond those doors, he could focus on finding some way to free his hunter from the evil that was eating him from the inside out.

In the back of his mind, he knew leaving in the middle of the night like this was cowardly, but it was the only way.

With one last look around the dimly lit bunker, he started up. He only made it a few steps before a deep voice stopped him.

"Cas."

Castiel looked back to see Dean approaching with suspicion etched deeply into the weary lines of his face. His hair was mussed and his sleep clothes rumpled. He stopped at the bottom of the stairs with one hand on the banister rail in a white knuckled grip.

"Cas, what are you doing?"

"Dean. You should be sleeping."

"Are you leaving?" When Cas only held his gaze, the suspicion melted from Dean's face to be replaced by a look so full of hurt it made the angel flush with guilt. "You are. You're leaving, and you're not coming back."

Castiel dropped his eyes. "Yes."

"You're leaving," Dean repeated, as if he were trying to make sense of the words.

Cas slipped the strap of his duffel from his shoulder and eased the bag down to the step. "I'm sorry, Dean, but I can't be here."

"_Why?_" The devastation behind that one word flayed the angel open to his core.

"Dean, I can't sit by and watch you be destroyed by the Mark!" He didn't want to hurt Dean, but once the words started coming, they all tumbled out. "You've stopped fighting. You've resigned yourself to it as if there's no hope. You haven't yet given _in_ to the Mark, but you _have_ given _up_. Out there, I can search for a cure, but here? Watching you die by inches without a fight? It _will_ kill me. I can't watch it happen, Dean. I won't."

"I'm not..." Dean's denial trailed off unfinished. "Cas, please."

Castiel shook his head and leaned down to pick up the strap of his duffel, though he didn't lift the bag. "I'm sorry, Dean. I need to go. I have to."

"Wait! Please, Cas, don't leave!" His voice was ragged as he reached his free hand toward the angel. "I told you before that I need you. I _need_ you, man – I do! And right now? I need you more than I ever have. I can't get through this without you. _Please_, Cas! Don't leave me."

Castiel's resolve wavered at the hunter's raw plea, and he struggled to stay strong. He needed to go. Now. Protect himself and save Dean. Take his bag and go find a cure. His feet moved, but they took him a step down instead of up.

Dean's reaching fingers pulled back and curled into a fist at his side. His face rippled with the strain of forcing the words out while still sandbagging the tsunami of emotion behind them. "Truth is, I'm afraid. I'm scared to death of this thing. I'm freakin' terrified of what it's making me into. I don't want to die, but...man, I don't think I _can_ fight this. It's just too strong."

All the angel's resistance crumbled when tears spilled down Dean's red-blotched face. Castiel dropped the duffel's strap and moved to the step just above the hunter. He reached out to brush his thumb along a tear-stained cheek, and as if the levee had finally burst, Dean fell against him, flinging his arms tight around the angel's ribs and burrowing his face into the crook of his neck. Castiel held Dean close as his whole body shook in silent sobs. He pressed his cheek to Dean's temple and stroked the hair on the back of his head, letting him purge some of his pent up fear. Dean clutched at Castiel's back, his gulping breaths coming harder as his sobs became not so silent.

"I'm scared, Cas! Don't go!" Tears made the words nearly indecipherable as Dean mumbled them over and over against Cas's collar.

Castiel held him, murmuring soothing nonsense until the hunter eventually brought himself back under control. But even after his breathing had returned to normal, Dean didn't pull away. He seemed content to simply stand there wrapped in the angel's embrace.

"Cas?" Dean didn't raise his head, so the words were thick and muffled. "Why would you leave without telling me? Why didn't you at least come say goodbye?"

"Because I knew that if I talked to you...you would convince me to stay."

Dean went very still in his arms, not even breathing, until he finally asked, "Does that mean you'll stay?"

Castiel sighed in defeat. "Yes."

Lifting his head at last, he met Cas's eyes with his own puffy, red-rimmed ones. "Really?"

The angel nodded, and Dean gave him a soppy, wet half-smile and released a breath that was almost laughter.

"Thank you."

Angel and hunter held their gaze for a long time before Dean took a step back as though suddenly aware of their closeness. He sniffed mightily and wiped off his cheeks. He glanced back up to Cas and cleared his throat roughly. "I'm, uh, sorry about that. Didn't mean to go all wussy meltdown on you there. If you could maybe not mention it to Sammy, I'd appreciate it."

Castiel stepped down off the stair so Dean wouldn't have to look up at him anymore. He placed a gentle hand to the man's jaw. "You aren't weak, Dean. You're shouldering a terrible burden – even more than the usual weight of the world you insist on carrying. If you want me here, I'll stay and do what I can to help you. I only ask that you don't stop fighting. Please don't give up hope."

Reaching up, Dean clasped Cas's hand where it cupped his cheek. "I won't. I promise."


	4. Chapter 4

**Heartfelt thanks to anyone reading this, especially those who have followed, favorited, and/or reviewed. That goes double extra for vickih, who is the bestest.**

**Reminder: Happily ever after NOT included. Bail now if that's not your cup of tea!**

**Disclaimer: Much as I would like it to, Supernatural does not belong to me.**

* * *

"Promise me you'll kill me when the time comes."

Dean's words cut through the air like shrapnel and buried themselves deep in Castiel's heart. The shock of pain left the angel momentarily breathless. With shaking hands, he placed the box of files he'd been carrying onto the stack to be returned to the archives. Carefully composing his face, he turned to see Dean watching him closely from the doorway of the library.

The man was haggard from the ever-growing strain on him, but he seemed completely calm. In the two weeks that had passed since Dean had stopped Castiel from leaving, they'd found no further leads to follow in their search for a cure. All four of them were exhausted and irritable, Sam in particular. But still they pushed on. As he'd agreed, Dean was trying hard not to give up, but hope was wearing thin for them all.

"Dean..."

"I mean it, Cas. Please don't let me hurt anyone else." He spoke firmly, and the eerie serenity of his manner set the angel on alert.

"What's wrong? Why are you asking this now?"

Dean's mouth stretched in a smile that didn't touch his eyes. "Nothing's wrong that wasn't wrong already. I just need to know I can count on you to do that for me. I can't ask Sam – I couldn't put that on him. Plus the Mark won't let me go easy. Since you're juiced up again, I'm pretty sure you can kill me and make sure I stay dead."

Something deep down inside Castiel went crackling, icy cold.

Despite his fears about the whole dire situation, it'd never truly hit home that they might fail. They'd prevailed in far more difficult predicaments. But what if they couldn't this time? The possibility that Dean might actually succumb to the Mark's power was suddenly horrifyingly real. If that happened, he would be lost to the angel forever.

He turned his back and clutched at the bookshelves to keep from sinking to the floor.

Since that night on the stairs two weeks ago, Castiel had stayed with the hunter, forcing down his own fears in order to be whatever Dean needed – moral support, a sounding board, a shoulder to cry on. He was sick with terror and heartbreak, but Dean needed him, so he soldiered on. But this? He couldn't do this.

"Cas?"

Dean's rough voice in his ear brought him back out of his head. The hunter was steadying him with one hand on his shoulder and the other at his wrist.

"Come on, man. Let's go sit down before you fall down." The words were gentle and soothing and they did absolutely nothing to thaw the icy fear in Castiel's heart.

Dean guided him away from the shelves and over to one of the couches, settling him at one end and sinking down beside him. Castiel stared down at Dean's hand still at his wrist. It was so different from his own hand – broader, more tanned, and rough with fading calluses. It bore barked knuckles, nicks, and many long-healed scars. It was beautiful. Soon Castiel wouldn't be able to compare them for those little differences. Soon Dean would be dead by the angel's hand.

Dean lifted his hand to Castiel's chin, turning him to examine his face. "Hey, buddy, what just happened?"

A different kind of pain filtered through the haze. Buddy. Dean's buddy. His pal. Just the kind of friend you can ask to murder you.

Castiel closed his eyes and shrank away from the hunter's touch, tension thrumming through him. "Please, Dean. You can't ask this of me."

Dean sighed and sat back a little on the couch. "Cas, if there was any other way, you know I'd take it."

The angel leaped to his feet and snatched up another box of ancient manuscripts. "There _is_ another way. We'll find a cure. We just have to look harder!" He thumped the box down onto the heavy oak table in the middle of the room and dug through it.

"We're looking, yes, but we're running out of time. It's getting close, Cas – I can feel it. I need to know you won't let me hurt more people." Dean had followed him to the table.

Castiel shook his head, trying to shut it all out. "Dean, no. No."

"I need you to do this for me. Cas, please." Dean reached out to grip his shoulder.

"I _can't!_" All through the bunker lights flickered and sparked as Castiel snapped. Power surged through his body as all the fear and pain he'd been tamping down coalesced into a blinding rage. Glass from the fixtures above them exploded into a glittering rain.

Castiel lashed out with his power, and the built-in bookshelves he'd clung to for support moments ago tore away from the walls and splintered across the floor, books and papers scattering everywhere. The act of mindless destruction felt _incredibly _good.

He whirled around to snarl in Dean's face. "I already have to stand by and watch you die! You can't make me be the one to _kill you!_" Howling the last words, the angel grabbed the edge of the table and flung it into the far wall, narrowly missing the hunter and leaving the furniture as so much plaster-dusted kindling. He was dimly aware that Sam and Charlie had come running, weapons and flashlights in hand, but Dean waylaid them at the door, reassuring them that he would handle it.

Ignoring them completely, Castiel continued venting his fury on the room, upending furniture and smashing walls until he was reduced to tearing apart individual books. When the rage finally burned itself out, he was left sitting limply in the middle of the destruction, breathing hard and shaking with grief for the man he hadn't even lost yet.

Dean approached cautiously and sat beside him in the debris, wrapping his arms around the angel. Castiel leaned into the embrace, pulling his hunter closer with fists bunched in his flannel shirt. Dean rocked him gently as they clung to each other in the dark.

"Cas? You okay?"

Castiel made a rude noise. "No, I'm not okay. I'm anything but okay."

"Right. Sorry." Dean at least had the decency to sound contrite.

They sat together a good long while, neither of them making a move to get up. At one point, Sam and Charlie peeked back through the doorway, but Dean waved them away so they were alone again. Castiel was grateful. He just wanted to be held by his hunter for a little while longer.

"I'm so sorry, Cas. I should have realized how hard this is for you," Dean murmured. "You've been covering it so well, I didn't know. I'm sorry."

Guilt nudged into the aching sorrow. "I didn't want you to worry."

Dean laughed a little sadly. "You shouldn't use me as an example of how to deal with your feelings, you know. Sammy's always told me bottling everything up ain't healthy."

"Apparently not."

"Do you at least feel a little better? I always feel better after a good tantrum."

Scowling into Dean's shirt, he considered snapping at him again, but instead settled on the truth. "A little, yes."

The hunter's palm rubbed up and down Castiel's back. "That's my angel."


	5. Chapter 5

**Disclaimer: *sigh* Supernatural doesn't belong to me.**

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After the incident in the library, Dean didn't mention it again – wanting Castiel to kill him when he fell to the Mark's influence. At least, not aloud. The angel knew Dean still needed him to do it when the time came. There was no one else. As the hunter had pointed out, Cas was likely the only one who could make sure he stayed dead.

As the days passed, the four of them grew more desperate, spending nearly every waking moment digging for clues to a cure. None of them slept much anymore, though they all encouraged Dean not to push himself. Occasionally, Charlie or Sam would leave the bunker to follow up on a lead, but they always came back empty handed. Sam began disappearing more often and for longer periods. Castiel assumed he just needed some time to himself.

Dean was edgy and overly sensitive, snapping at people for the slightest things. He was prone to zoning out, and when he would shake himself back to awareness, Cas always thought he looked a little frightened. His temper became increasingly volatile, so he began spending more and more time sequestered in his bedroom.

When Dean refused to talk to anyone and didn't come out for several days, Charlie shooed Castiel down the hallway to his door, telling him to check on Dean and not to leave until he talked to him.

He knocked gently and called out, "Dean?"

When there was no answer, he tried the knob, but it was locked. "Dean, please open the door."

There was still no response, so Castiel knocked harder. "Let me in, or I'm coming in anyway."

A muffled curse was audible, followed by a click as the lock was released, but the door stayed closed.

Castiel turned the knob and stepped inside, only to stop in shock at the sight of the hunter. Dean was just settling back onto his bed, placing headphones over his ears and shutting his eyes. He was drawn and thin. Shadows darkened his eyes and cheeks, and his lips were pale. His soul still shone from within, but the light – normally so bright and pure – was faded, flickering with the blackness creeping around it. The angel hadn't seen Dean look worse since he'd first laid eyes on him in Hell itself.

"You look awful," he told the hunter.

"Gee, thanks, Miss Manners. I feel so much better now."

Castiel sat at the foot of the bed. "Talk to me."

Dean's sunken eyes opened to fix on him. They were a dull green, lacking the spark that normally made them so beautiful. They were frightening.

Dean closed his eyes once again. "Go away."

"No."

The eyes flew open again, this time in anger. His lip pulled back in a snarl. "Get out, or I'll throw your ass out."

Castiel shook his head gently. "I'm not here to fight, Dean. I need you to tell me how you are. It's not safe for us not to know."

It was cheating, but Cas knew that Dean's fear of hurting his friends and family would force him to talk.

"Damn you, anyway," Dean growled, pulling the headphones off. "It's bad, all right? I can't be around anyone else right now. I'm angry all the time, and every little thing sets it off worse. Voices. Footsteps. The sound of people freakin' _breathing_ pisses me off so bad I see blood. If I stay in here with the music up, it all sort of goes away for a while. Not completely, but to a level I can manage. For now. Now please go away."

"Thank you, Dean." The angel stood to leave, but paused in thought. "Dean?"

"_What?_" he spat.

"I'd like to try something."

Dean narrowed his eyes suspiciously. "Try what?"

"I'd like to see if my Grace can help you manage the influence of the Mark."

"What the hell does that mean?"

"It's just a touch, as if to heal you or soothe nightmares. It might offer some relief."

Dean thought it over, then nodded hesitantly. Castiel moved closer and touched two fingers to the hunter's forehead. When the angel's Grace touched him, Dean gasped sharply, then slowly relaxed back against the bed. It was harder for Castiel to pull back this time. The blackness of the Mark clung and pulled at his Grace, trying to suck him in, and when he finally freed himself, it left a residue.

Castiel tried not to let the slick, creeping feeling bother him. He asked, "Any better?"

Though he still looked terrible, Dean gave a small, grateful smile. "A little, yeah." He squinted at Cas again. "So. Exactly whose nightmares have you been soothing?"

A guilty flush warmed Castiel's face. "I only wanted to help you rest. I apologize if that was a breach of your trust."

Dean dropped his chin to his chest, shaking his head as though he just didn't know what to do with the angel. "You know that's creepy as hell, right?"

"You have said so, yes."

Green eyes bored steadily into Castiel. At last Dean gave a single dip of his chin and said, "Thanks. For caring enough to do it anyway." He crossed his arms over his chest. "So how often can you do that? How long will it last?"

Castiel shivered a little as the black residue squirmed at his fingertips. "I don't know. It'll likely become less effective as the Mark grows stronger. Call to me when you feel you need to, and I'll do what I can."

He stood to leave the hunter to his music, but Dean's hand caught his and held it.

"Wait. Would you stay a while? It's the first I've been able to stand being around somebody in days. It'd be nice to have some company for as long as I can manage it."

Dean hadn't yet released him, and Castiel looked down at their joined hands. He wanted to sear the image into his memory before his chances for moments like this were gone forever. Looking up again to meet the tired eyes, the angel smiled.

"I would like that."

Dean moved over to make room, and Cas sat at the edge of the bed. With an impatient grunt, Dean tugged at his hand, pulling him down to lie beside him. "Come here," he grumbled. "I miss you."

He pulled Castiel closer until he was tucked right up against his side, resting his head in the hollow of the hunter's shoulder, with a hand on his chest. Dean's arms around him were a warm and comforting weight. A thick, heavy emotion he couldn't decipher welled up, pushing its way into Castiel's throat. A longing, perhaps, or mourning for a future that could never be.

Charlie's words from all those weeks ago came to the forefront of his mind. Opportunities to tell Dean how he felt were slipping by, and, like it or not, soon they would be gone. The urge to tell him was growing strong, but still he held back, fearing that Dean would react badly. That rejection, so close to the end, would devastate him.

But maybe that didn't matter. Dean deserved to know. The man who lived his life believing he was unworthy of love deserved to know he was loved utterly, even if he didn't return the feeling.

Castiel raised his head just enough to see Dean's face. His eyes were closed, and silent tears streamed down his cheeks as he held his angel tight.

Soon. Castiel would tell him soon.


	6. Chapter 6

**Disclaimer: Alas, Supernatural does not belong to me.**

* * *

After that night, Dean leaned heavily on Cas for support. Castiel did his best to ameliorate the effects of the Mark with the influence of his Grace, but as he'd expected, it helped less and less as the days passed. He continued to try even though his Grace became more tainted each time. He didn't tell Dean about that.

Charlie and Sam still worked doggedly, seeking an answer. Sam was gone from the bunker more often than not, but when he was around, he was absolutely relentless in his efforts and terrifying in his intensity – scouring books and muttering an endless mantra that they "almost had it" and were "so close".

Without meaning to, Castiel slowly began to accept that they might not succeed. Instead of researching, he felt his time was better spent providing what comfort he could to his hunter. Dean wanted him at his side almost constantly now, so the angel stayed. During the days, he tried to ease Dean's pain, soothed his unpredictable moods, kept him company, and encouraged him to eat. At night, he took his own comfort in being held tightly in Dean's arms and listening to his heart beat.

Sometimes Dean would lose his temper and erupt in violence. Each time, he managed to rein it in and fight back the endless wash of blood that he said flooded his vision. One afternoon, he gathered up every knife, machete, and gun from his room and threw them into the hallway. He said he was afraid of how they made him feel.

Whenever any kind of outburst happened, Dean would throw long looks at Castiel, begging with his eyes for what he wouldn't ask aloud. But the angel knew it wasn't time yet. Soon, but not yet.

Castiel still hadn't told Dean he loved him.

* * *

Dean had finally fallen asleep after a particularly difficult day. He'd gone to bed early, but curled on his side facing away from Castiel. The angel had joined him on the bed but kept his distance. He lay on his side, head propped on his hand to watch over his hunter as he slept fitfully. Dean twitched and whimpered with every labored breath.

Castiel's most recent attempts to ease the strain of the Mark seemed to have no effect. Their time was finally up - he was certain of it. Somehow, he expected it to hurt more. Of course it did hurt. A _lot_. But he'd been living with the knowledge of how this would end for so many weeks, he supposed he'd somehow gotten used to the idea. That was worse than anything else.

He reached out to stroke his fingers down the side of Dean's pinched face. He kept his Grace back, and just touched his hunter for touching's sake. Closing his eyes, he tried to memorize the feel of skin and stubble under his fingers. He breathed deeply, taking in the familiar mix of scents – sweat, gun oil, and leather, but something else as well that just made Dean smell like Dean.

Life without Dean Winchester. It seemed impossible to Cas, despite his having survived just fine for many millennia before the man was ever born. The moment he touched Dean's soul in Hell, Castiel was forever changed.

He lay back against the pillow and closed his eyes. As he drifted off to sleep, he decided he would do it. In the morning, he would tell Dean he loved him.

* * *

"_Stop me._"

Castiel jerked awake to a crushing pressure on his wrist and the cloying stink of black magic in the air. Dean was crouched at the side of the bed, wild-eyed and panting. One hand had an unnaturally strong grip on the angel's wrist and the other held a long knife that gleamed in the darkness.

"You need to _stop me!_" Dean hissed. He was shuddering as he tried to gain control over himself. "Cas, _please!_"

Castiel froze in horror. Dean was lost to the Mark of Cain. His hunter was gone.

He hesitated too long. In an instant, Dean's eyes flashed demon black, and he smiled wide. "Sorry, angel. Too late." And with the superhuman strength of the Mark, he slashed the knife twice across Castiel's abdomen.

The pain of the attack was less the shock of it. Before Castiel could so much as cover the wounds, Dean threw him across the room to smash against the wall and drop to the floor. He heard Dean laughing his way down the hall, banging on doors and walls and calling out in a sing-song voice for Sam and Charlie to come out to play.

Castiel sent his Grace flowing to the wounds. They were extremely deep, and his tainted Grace was slow to heal them. He gasped at the agony of forcing tissues to knit themselves painfully together, but he pushed through as quickly as he could. Dean had to be stopped.

By the time he regained his feet, a scream echoed throughout the bunker. He staggered down the hall, following the noise of shouts and crashes toward the armory. Already covered in blood, Sam and Charlie were scrambling to keep their feet in the fight against Dean, but he just seemed to be teasing them – enjoying the chase. He'd already broken into the armory and along with his knife, he now carried an archangel's blade.

Determined not to fail Dean, Castiel rushed in, hand outstretched to smite the one creature he loved above all others.

At the last second, Dean spun to face him, knocking aside the hand. He launched himself into the angel, bringing them both to the floor. Holding Castiel by the throat, he drew back the angel blade, but Cas caught his wrist and held him back. Dean roared and struggled to drive the blade into the angel's chest.

"I told you to kill me! _Why didn't you kill me?_"

In that moment, time slowed down for Castiel, and he saw everything so sharp and clear it hurt his eyes. He saw Sam and Charlie scrambling forward to try and pull Dean off the angel. He saw Dean's face contorted in his blood lust. Saw his beautiful green eyes burning in madness, and his muscles bunched and straining as he tried to pierce him with the shining angel blade.

Perhaps it was habit, but his eyes were pulled once again to where their hands joined. And as he focused on that point of contact, he felt the familiar, grotesque pull of the Mark's blackness on his Grace. He watched as a trickle of blue-white light passed from his hand to Dean's arm and up to the Mark itself. Instead of being absorbed by the blackness, his Grace flowed over the Mark and glowed more brightly.

Without questioning it in the slightest, Castiel slapped his other hand over the Mark of Cain and poured all his power into it.

Instantly, he screamed as his whole world became blinding agony. It felt as though his Grace itself had caught fire. The moment he released it, it surged forward all on its own, tearing itself from his body to be sucked down into the Mark. It ripped through him as it went, searing every nerve as it poured outward.

Dean howled and jerked back, trying to free himself from Castiel's grasp, but the angel couldn't let go even if he'd wanted to. A brilliant white pinpoint of light leaked from beneath his hand. Dean screamed and thrashed as the light burned hotter and brighter until even Castiel had to look away.

"Cover your eyes!" the angel shouted, just before he felt a horrible tearing sensation as the last of his Grace uprooted itself and flooded the Mark.

The light blazed brilliant white, filling the room until there was nothing but light and pain and the sound of Dean's agonized screams. Then it grew to block out the screaming.

And then there was nothing but white.


	7. Chapter 7

**Welcome to the final chapter. My goal was to finish this little beast before the next episode aired, and I actually managed it. **

**Also? I'm sorry.**

**Disclaimer: Supernatural does not belong to me.**

* * *

A strangely hollow pain was the first thing Castiel felt when he returned to the beginnings of awareness. Pain, followed by an oily sickness that slithered unpleasantly through his body. Sounds began to filter in. At first it was a jumbled clamor in his muddled mind, then gradually became clearer.

"Dammit, Dean, you were _dying!_ I had to do something!"

"No, Sam! You really fucking didn't! Haven't you learned by now that the secrets and lies and _bullshit_ only ever make things worse?"

"The Book had answers – I couldn't let that go!"

"So you go to Rowena behind everyone's back? _Rowena?_ What in the everloving fuck is wrong with you? And now look at him, Sam! _Look at him!_"

"I had no idea-"

There was a meaty sound followed by scuffling and a solid thump. They sounded so angry – it was upsetting. "_Fuck_ you, Sam! There's exactly one way I will ever forgive you for this. You go find her. You bring her skanky bitch ass here right now, and you make her _fix him!_ Understand me? If he dies, Sam, I swear to God, I'll kill you both with my bare hands. Now _get the fuck out!_"

The pain was overlaid by other sensations now. He was on the floor. There were small, warm hands on him. Mustering every bit of strength he had, Castiel opened his eyes.

When the blur came mostly into focus, he saw Charlie above him with blood trickling from a gash on her cheekbone. Charlie was his friend. He tried to reach out to heal her, but he couldn't move beyond a few twitches. Charlie's face turned his way.

"Guys? Hey, guys?" Her voice was terribly sharp, and her face was wet. She was upset, too. "His eyes are open!"

"Go, Sam! Bring that evil bitch here!"

Dean's face came into view, and Castiel smiled. A callused hand cupped his face and stroked his hair. Another came to rest on his chest. It felt nice, even through the pain. Wherever Dean touched, the slick darkness inside him retreated a little.

"Cas! Are you okay?"

Castiel tried to come up with words, but couldn't find any. He smiled again, happy Dean was there with him.

"Dean, I don't think he can talk," Charlie murmured.

"Fuck," muttered Dean. He was using a lot of profanity. He must be _very_ upset. "All right, Cas, you hang on, okay? You're gonna be all right. Sam's bringing that whore witch back here to fix you up, so you just stick with us."

Castiel frowned, confused as to who the whore witch was.

Dean's thumb rubbed gently at the lines between Castiel's brows, smoothing them out again. "Rowena. Sam the backstabbing _liar_ didn't burn the Book of the Damned and gave it to Rowena to find a cure. Bitch found one, all right. She couldn't remove the Mark, but she could change it."

The words flowed over Castiel's ears like music. Dean's voice was so beautiful. The sound of it pushed the pain back.

"When she cast the spell, it brought out the Mark, but made it vulnerable to an angel's Grace. We think the Mark and your Grace destroyed each other."

Castiel tipped his head. That wasn't true. He could still see faint remnants of his Grace sizzling over Dean's skin, washing away the last of the blackness marring his soul. And the creeping sickness inside himself was still there, too, though he had no Grace left to fight it with.

He remembered then. Dean had been sick. Dying. He struggled to say something, but he couldn't move properly.

"Whoa, hey, it's okay, Cas! Settle down!"

Charlie put a hand on Dean's arm. "It's you, Dean. He's worried about you."

"Shit, Cas, I'm just fine. Mark's gone, see?" He held out his unblemished arm. "It's you we're worried about!"

Castiel relaxed. Dean was safe, so everything was okay. His eyes were heavy, so he let them drift closed.

"Cas? Come on, man, stay with me!" The rough hand patted his cheek, then shook him. "Cas, dammit wake up! Shit! Where the hell is Sam?"

The hands went away and footsteps moved across the room.

Then Charlie's voice came. "He just left – he'll be back as soon as he can. Dean!" The smaller hands went away then, and quick footsteps followed the first ones.

Castiel forced his eyes open again, but he was alone. The voices were somewhere else.

"Dean, stop it! You turn around and march your ass straight back in there, you frakking moron!"

Scuffling sounds drifted to him, followed by a deep-voiced yelp of pain.

"Dean, dammit, go to Cas! He needs you!"

"No, he needs that bitch Rowena, and I'm not waiting around for Sam anymore."

"_Dean!_ Listen. To. My. Words." Charlie's voice dropped, but still carried well enough to be heard. "Cas loves you, you stupid ass, and this could very well be your last chance to be with him. Do you hear me? Do you _understand_ what I'm saying to you?"

During the silence that followed, Castiel felt the slippery blackness move and stretch inside him. He whimpered. It hurt.

When the pain faded, Dean was there with him again. Castiel should have been happy he came back, but Dean looked so sad, it made him sad, too. Dean held his hand and touched his hair.

"Cas? Is it true? Do you love me?"

He smiled. Yes, of course he did. He loved Dean with all his heart. He'd do anything to protect him and make him happy. But Dean didn't look happy. His eyes shone with tears, and his lips quivered.

"Aw, shit, Cas. Why the hell didn't you tell me?" Dean pulled Castiel up, wrapping him in a tight hug. Castiel could feel the hot-then-cold touch of tears on his skin from Dean's cheek. Inside him, the blackness spasmed, trying to get away from Dean's touch. It hurt, but the hug felt better.

Dean cradled Castiel in his lap. He touched his face, wiping away the cold tears. He held his hand, squeezing it tightly to his chest. He pressed his forehead to Castiel's and looked at him with his beautiful green eyes. So sad, full of tears and regret.

"Cas, you know I love you, right? I'm shit with talking about this stuff, but you know I do, right? You're everything to me."

The happiness that filled Castiel's chest pushed back the pain for a few moments. Dean was safe, and he loved him. Everything was perfect.

But then the pain pushed back, and he closed his eyes against it.

"Oh, fuck. Charlie! Charlie, I need help!"

The squirming evil was taking hold. It slithered into every crevice and took root. It hurt. A lot.

"Oh my god, what is that? Dean, what's happening?"

"Shit, Charlie, I don't know! Fuck, I don't know! Cas? Can you hear me?"

The blackness began to bleed over everything. The voices began to fade.

"No – nononono, please don't leave me! Not like this. Cas? Come on, Cas! _Cas!_"

As the blackness closed over Castiel, the last thing he heard was his name, spoken by the beautiful, broken voice of the man he loved more than life.

"CAS!"

Everything was perfect.


End file.
